I'm a 16 year old girl and have a best friend same age and gender. We always mock flirted its part of high school but she's been giving out so pretty strong messages and I think she fancies me, I'm not so sure about my sexuality yet (I'm still a virgin) but I know she's been with girls before now, she's self harmed for a long time too and I think she needs a friend more than a girlfriend. How do I find out the truth and let her down gently?

If you're not sure about your sexuality, why don't you just see where this goes?

I'd just advise going with the flow. If she does make a pass at you or try to get it on with you, and YOU don't want to - just tell her. There's no need to make things more complicated than they already are.